Polymers of maleic acid with amines

ABSTRACT

Polymers of maleic acid may be prepared by thermally polymerizing malic acid, maleic acid or fumaric acid with less than one equivalent of ammonia. The polymers are modified by the incorporation of amines, carboxylic acids or combinations thereof. The polymers formed are excellent inhibitors of alkaline earth salt deposition, dispersants, tartar control additives, detergent additives, and water treatment agents.

This application is a division of application No. 08/132,246, filed Oct.6, 1993 U.S. Pat. No. 5,442,038.

FIELD OF THE INVENTION

This invention relates to polymers of maleic acid and amines.

DESCRIPTION OF RELATED ART

It is well known that polymers of ammonia and maleic acid can beprepared by thermal condensation of one or more equivalents of ammoniawith maleic acid, malic acid, fumaric acid or the mono- or diamides ofmaleic acid, malic acid or fumaric acid.

U.S. Pat. No. 4,839,461 discloses a method for making polyaspartic acidfrom maleic acid and ammonia by reacting these constituents in a 1:1-1.5molar ratio by raising the temperature to 120°-140° C. over a period of4-6 hours and maintaining it for 0-2 hours.

Dessaigne (Comp. rend. 31, 432-434 [1850]) prepared condensationproducts which gave aspartic acid on treatment with nitric orhydrochloric acid by dry distillation of the acid ammonium salts ofmalic fumaric or maleic acid at unspecified times and temperatures.

U.S. Pat. No. 3,846,380 discloses that polysuccinimide may be made byheat condensation of the following starting materials, aspartic acid;ammonium salts of aspartic acid, malic acid, maleic acid and fumaricacid; and mono- and diamides of aspartic acid, maleic acid, maleic acidand fumaric acid.

U.S. Pat. No. 4,696,981 discloses the formation of anhydropolysuccinicacid by the microwave radiation of ammonium salts of malic acid via theformation of ammonium maleate.

Jpn. Kokai 60,203,636 [C.A. 104, 207690m, 1986] discloses a method forthe synthesis of copolymers of aspartic acid by heating amides, ammoniumsalts or monoamide-ammonium salts of malic acid, maleic acid or/andfumaric acid with one or more amino acids at 180° C. for four hours.

A method of preparation of polyaspartate, useful for inhibition ofincrustations due to materials causing hardness in water and of value indetergent formulations, in which maleic acid or fumaric acid are reactedin a molar ratio of 1:1-2.1 at temperatures greater than 190° C.,followed by conversion of the polymer formed in this reaction to a saltof polyaspartic acid by basic hydrolysis is disclosed by U.S. patentapplication Ser. No. 08/007,376, filed May 14, 1992, by Louis L. Wood.

A method for obtaining higher molecular weight copolymers ofpolyaspartic acid, suitable for the inhibition of scale deposition, byreacting maleic acid and ammonia in a stoichiometric excess, with adiamine or a triamine, at 120°-350° C., preferably 180°-300° C., andthen converting the copolymer of polysuccinimide formed to a salt of acopolymer of polyaspartic acid by hydrolysis with a hydroxide isdisclosed in U.S. patent application Ser. No. 07/968,506, filed Oct. 10,1992 by Louis L. Wood.

Copolymers of polyamino acids formed by reaction of polysuccinimide withalkyl, alkenyl, aromatic amines or alkyl and alkenyl polyamines areuseful as inhibitors of mineral scale deposition are disclosed in U.S.patent application Ser. No. 07/968,319, filed Oct. 29, 1992 by Louis L.Wood and Gary J. Calton.

U.S. patent application Ser. No. 07/994,922, filed Dec. 22, 1992, byLouis L. Wood and Gary J. Calton, discloses copolymers of polyasparticacid which are suitable for the inhibition of scale deposition which areobtained by reacting maleic acid, an additional polycarboxylic acid andammonia in a stoichiometric excess, at 120°-350° C., preferably180°-300° C., to provide copolymers of polysuccinimide. In a secondembodiment, a polyamine was added to the reaction mix. Theseintermediate polysuccinimide copolymers could then be converted to thesalts of copolymers of polyaspartic acid by hydrolysis with a hydroxide.

U.S. patent application Ser. No. 08/031,856, filed Mar. 16, 1993 byLouis L. Wood, discloses a method for preparing copolymers of polyaminoacids by reaction of an alcohol with maleic anhydride to form the halfester followed by addition of ammonia, ammonia and an amine, or ammoniaand a polyamine. The mixture is then heated to 120°-350° C. to formpolysuccinimide or a derivative thereof. The resulting polysuccinimidemay be hydrolyzed to form its salt or reacted further to provide aderivative of polyaspartic acid.

It is also well known that maleic polymers can be obtained throughradical polymerization as disclosed in U.S. Pat. No. 5,064,563 andreferences cited therein.

SUMMARY OF THE INVENTION

We have found that useful polymers and salts thereof can be prepared bythermal condensation, at temperatures above 120° C., but preferablyabove 160° C. and more preferably above 190° C. for a time sufficient toremove the water of condensation, of less than one equivalent of anamine having the formula NHR'R" where R' and R" can be the same ordifferent and where R' and R" independently represent hydrogen or analkyl, a carboxy alkyl, an hydroxyalkyl, an alkenyl, an alkyl amine, oran alkyloxy amine, with a monomer selected from the group of monomersconsisting of maleic acid, malic acid, fumaric acid or maleic anhydride.Such polymers are easily formed when the amine is present at 0.05equivalent of amine per mole of monomer to less than 1 equivalent ofamine per mole of monomer. A preferred range of amine is 0.25 to lessthan 1 equivalent of amine per mole of monomer. An especially preferredrange of amine is 0.5 to less than 1 equivalent of amine per mole ofmonomer. Amines such as ammonia or those having at least one primary orsecondary amine are useful in formation of the polymers. Moleculeshaving additional amine groups consisting of at least one or moreprimary or secondary amines are of value in extending the molecularweight of the polymer. Illustrative of the types of amines which mightbe used are alkyl amines having 1-36 carbons, polyoxyalkyleneamines,polyoxyalkylenediamines, polyoxyalkylenetriamines, alkyl diamines suchas ethylene diamine or hexanediamine, alkyltriamines such as diethylenetriamine or melamine, or amino acids such as lysine and arginine.Permutations and combinations of the various amines provide polymers,all of which have useful properties, to a greater or lesser degree, asdescribed below. The process for synthesis of the polymers comprisespolymerizing (1) one of the members of the group consisting of maleicacid, malic acid, and fumaric acid and (2) less than one equivalent ofammonia, at a temperature greater than about 120° C., to produce saidpolymer; polymerizing (1) one of the members of the group consisting ofmaleic acid, malic acid, and fumaric acid, (2) less than one equivalentof ammonia and (3) an amine, at a temperature greater than about 120°C., to produce said polymer; polymerizing (1) one of the members of thegroup consisting of maleic acid, malic acid, and fumaric acid, (2) lessthan one equivalent of ammonia, and (3) a carboxylic acid, at atemperature greater than about 120° C., to produce said polymer; orpolymerizing (1) one of the members of the group consisting of maleicacid, malic acid, and fumaric acid, (2) less than one equivalent ofammonia, (3) an amine and (4) a carboxylic acid, at a temperaturegreater than about 120° C., to produce said polymer. The polymer may behydrolyzed to form a salt having high carboxyl functionality by furtherreacting said polymer with a salt of an alkali, an alkaline earth metalor ammonia which is capable of hydrolyzing said polymer. Among thosesalts capable are the oxides, carbonates or other weak acid salts, suchas those of organic acids, and hydroxides of the alkali or alkalineearth elements, or ammonium hydroxide. Each of these hydrolysatesprovides a salt of the polymer wherein the counter-ion of the salt is anion of an alkali, an alkaline earth metal or ammonia. Other carboxylicacids may be incorporated providing a variation in thehydrophobic/hydrophilic ratio and varying the interatomic distancebetween carboxylic acid functionalities. Illustrative examples of suchacids are monocarboxylic acids such as alkyl carboxylic acids containing1-36 carbons, for example stearic, oleic, N-methyl-N-lauric, andpalmitic acids, amino acids such as alanine, lysine and polycarboxylicacids such as adipic acid, citric acid, fumaric acid, malic acid,malonic acid, succinic acid, glutaric acid, oxalic acid, pimelic acid,itaconic acid, nonanedioic acid, dodecanedioic acid, octanedioic acid,isophthalic acid, terphthalic acid, phthalic acid or polycarboxylicacids, such as aspartic acid or glutamic acid. The molecular weight ofthese polymers, with or without the inclusion of alternate carboxylicacids, may be extended by substituting a polyamine for a portion of theammonia used.

The polymer formed may then be hydrolyzed to give a water solublepolycarboxylic acid salt. The alkaline hydrolysis is carried out for asuitable time at a temperature in the range of 0° to 50° C., and ifnecessary, with cooling. The reaction is generally complete afterseveral minutes, but it may take several hours, in some cases, before itgoes to completion. The alkali hydroxides or carbonates of alkali metalsand alkaline earth metals, for example, NaOH, KOH, LiOH, RbOH, CsOH, Li₂CO₃, Na₂ CO₃, Rb₂ CO₃, Cs₂ CO₃, Ba(OH)₂, etc., may be employed as wellas the salts of the alkali or alkaline earth metals with a weak Lewisacid, where the pH of the salt in aqueous solution is above 5.5.Illustrative examples of these salts are the sodium salts of carbonicacid, acetic acid, formic acid and the like. The concentration of alkaliemployed can be varied widely depending upon the number of hydrophobicgroups in the material to be hydrolyzed, but the preferred concentrationis in the range of 0.1 to 10 N. The hydrolysis product may provide bothalpha and beta carboxyl groups to the amines. This ratio may vary due tothe strength of the hydrolyzing agent; however all of the hydrolyzingagents tested have given excellent activities in the testing carriedout.

At the present time, the structure of the polymers is unknown, andalthough not wishing to be held to any theory, the lack of an equivalentamount of an amine in the reaction with maleic acid would appear topreclude the formation of a strict polyamide, as has been suggested tooccur by a number of authors concerning the thermal polymerization ofmaleic acid with more than one equivalent of an amine. Studies of themechanism of the anionic polymerization of maleic anhydride catalyzed bytriphenyl phosphine and tributyl phosphine, showed the formation ofsuccinic anhydride units and cyclopentanone units or ketoolefinic units.Such units, along with their nitrogen containing analogs may wellpresent in the polymer of the present invention, most probably randomlyinterspersed in the polymer chain.

The polymers of the present invention provide properties which aredifferent from their counterparts prepared with one or more equivalentsof amine. The polymers also provide materials which are distinctlyadvantageous in their lighter color. The economic advantage due toreduced quantities of ammonia provides an economic incentive for theiruse.

The polymers are valuable intermediates which may be reacted further,for instance, after the manner of Jacquest, et al, U.S. Pat. No.4,363,797, Fujimoto et al, U.S. Pat. No. 3,846,380 or Wood, U.S. patentapplication Ser. No.08/031,856 filed Oct. 6, 1993, issued as U.S. Pat.No. 5,442,038 on Aug. 15, 1995.

The salts of these polymers are valuable as solubilizing agents,dispersing agents, emulsifying agents, rust-proofing agents,fiber-treating agents, level dyeing agents and retarding agents,inhibitors of metal scale deposition and inhibitors of corrosion offerrous metals. As dispersing agents, they are useful in suspendingpaints, coal, clay, pigments and paper fibers, to provide evensuspensions, pumpable fluids and to prevent settling of sediments, forinstance. The inhibition of metal scale deposition by these polymersalts may occur by prevention of nucleation of salts such as those ofcalcium, strontium, barium and magnesium in waters as well as byprevention of crystal growth by the addition effective amount of a thesalt of the polymers. The use of said polymer salts in water treatmentmay also be desirable as a result of disruption of the crystal patternof the metal salt, making a scale which is more easily removed. Thus,the incorporation of these salts or polymers into water treatmentcomposition, which include a scale deposition inhibition effectiveamount of the salt, or polymer which may be hydrolyzed in situ, providesan effective water treatment composition. These polymer salts are usefulwhen incorporated into laundry and dishwashing detergents as suspendingagents or to prevent metal salt deposition on clothing, glassware ormetal objects. The salts may be incorporated in oral health careproducts to prevent the accumulation of tartar on the teeth or onporcelain objects used in the mouth. Zinc salts are very useful in oralhealth care. They are especially useful in dentrifice compositions forinhibition of tartar deposition in effective amount of the salts of thepolymers in combination with an orally acceptable dentrifice compositioncompatible with said salt, and more especially in the form of an oralhygiene formulation such as mouthwashes, rinses, irrigating solutions,abrasive gel dentrifices, nonabrasive gel dentrifices, denturecleansers, coated dental floss, interdental stimulator coatings, chewinggums, lozenges, breath freshener, foams and sprays. They are useful intreating cloth and fibers as warp sizing compounds.

The addition of the polymer itself to the detergent formulation may bedesirable where the pH of the detergent is sufficient to causehydrolysis of the polymer yielding the salt in situ.

One object of this invention is to provide novel compositions useful assolubilizing agents, dispersing agents, emulsifying agents,rust-proofing agents, fiber-treating agents, level dyeing agents andretarding agents, inhibitors of scale deposition, inhibitors ofcorrosion of ferrous metals, inhibitors of scale formation in hardwater, boiler water, cooling water, oil well waters, agricultural spraysand irrigation water and as builders and dispersants in detergentformulations.

Another object is to provide a method of producing these novel polymers.

Yet another object is to provide compositions suitable for incorporationin oral health care products for the inhibition of dental calculus.

A final object is to provide methods for preventing scale formationwhich are effective, low in cost, and environmentally benign.

DETAILED DESCRIPTION OF THE EMBODIMENTS EXAMPLE 1

A solution of 39.2 g (0.4 moles) of maleic anhydride in 40 ml of waterwere stirred at 25°-75° C. for 45 min to give a white slurry of maleicacid. To this slurry was added 42 g of 30% aqueous ammonium hydroxide(0.36 moles NH₃, 90% of theoretical required) with stirring and cooling.The resultant clear solution was then tumbled at 180°-200° C. (salt bathtemperature) for 10 min to give a tan solid. The solids were pulverizedand tumbled for 10 min at 200°-225° C. Once again the solids werepulverized and then tumbled at 225°-240° C. for 10 min. Finally, thesolids were pulverized and tumbled for 10 min at 230°-240° C. to give39.3 g of tan powder which was insoluble in water.

EXAMPLE 2

The procedure of Example 1 was repeated using 35 g of 30% aqueousammonium hydroxide (0.3 moles NH₃, 75% of theoretical required) to give39.3 g of pink-tan powder which was insoluble in water.

EXAMPLE 3

The procedure of Example 1 was repeated using 23.5 g of 30% aqueousammonium hydroxide (0.2 moles NH₃, 50% of theoretical required) to give37.8 g of pink-tan powder which was insoluble in water.

EXAMPLE 4

The procedure of Example 1 was repeated using 11.6 g of 30% aqueousammonium hydroxide (0.1 moles NH₃, 25% of theoretical required) to give36.3 g of pink-tan powder which was soluble in water.

EXAMPLE 5

Four gram portions of the solids from Examples 1-4 were each dissolved9.0 g of water containing 1.25 g of NaOH to give clear red-brownsolutions, pH 7.5-8.5, estimated to contain 36-37% solids. Gelpermeation chromatography (GPC) was run on a 1 cm×18 cm, Sephadex G-50column in a mobile phase of 0.02 M sodium phosphate buffer, pH 7.0,running at 0.5 ml/min, with detection in the UV at 240 nm. Table 1 showsthe results which were obtained.

                  TABLE 1                                                         ______________________________________                                        Sample      Residence time (min)                                              ______________________________________                                        Example 1   21.5                                                              Example 2   21.0                                                              Example 3   23.0                                                              Example 4   31.0                                                              ______________________________________                                    

EXAMPLE 6. Preparation of a maleic polymer with a polyamine

To a solution of 4.6 g (0.025 moles) of lysine in 40 g of watercontaining 1.0 g of NaOH was added 39.2 g (0.4 moles) of maleicanhydride while stirring at 70°-75° C. for 10 min to give a pale yellowslurry of maleic acid. To this slurry was added 5.0 g (0.29 moles) ofanhydrous ammonia with stirring and cooling. This solution was thentreated with heat as in Example 1 to give 44.0 g of pink-tan powderwhich was insoluble in water.

A 4.0 g portion of the powder was dissolved in a solution of 9.0 g ofwater containing 1.3 g of NaOH to give a clear red-brown solution,estimated to contain 36% solids. Addition of 0.55g of 30% H₂ O₂ gave aclear yellow solution after 16 hrs at 25° C. Chromatography of thissolution as in Example 5 gave a peak centered at 13 min.

To prepare a 100% ammonia sample for comparison purposes, thisexperiment was carried out in the proportions above except that 1equivalent of ammonia was used (noted as 6a in the results).

EXAMPLE 7. Calcium sulfate inhibition assay.

The material to be tested as an inhibitor of calcium sulfate scaleformation was added in the quantities indicated to a solution of 10 mlof calcium chloride solutions 17.3 g of CaCl₂ dihydrate in 800 g ofwater containing 33 g of NaCl). To this solution was then added 10 ml ofsulfate solution (16.8 g of Na₂ SO₄ and 33 g NaCl in 800 ml of water).The mixture was then sealed and maintained at 65° C. for 16 hours.Finally the mixture was filtered through Whatman #2 paper and dried at65° C. for 8 hours, after which the weight of precipitate wasdetermined. The results In Table 2 were obtained.

                  TABLE 2                                                         ______________________________________                                                   percent of                                                                              CaSO.sub.4 Inhibition of Precipitation                   Sample from                                                                              equivalence        1.25 ppm                                                                              2.5 ppm                                 Example Number                                                                           of ammonia                                                                              0 ppm    (mg ppt)                                                                              (mg ppt)                                ______________________________________                                        blank                79.5                                                     1          90                 23      10                                      2          75                 4.5     1                                       3          50                 48      0                                       4          25                 51      35                                      a          100                37      19                                      6          75                 49      28                                      6a         100                52      14                                      polyaspartic acid             38      10                                      ______________________________________                                         .sup.a prepared by the method of Example 1 using 1 equivalent of ammonia 

EXAMPLE 8. Inhibition of calcium carbonate precipitation by the calciumdrift assay.

In this assay a supersaturated solution of calcium carbonate is formedby adding 29.1 ml of 0.55 M NaCl and 0.01 M KCl to 0.3 ml of 1.0 MCaCl₂, 5 microliter of sample (100 mg of the aqueous solution in 10 mlof water) and 0.6 ml of 0.5 M NaHCO₃. The reaction is initiated byadjusting the pH to 8.55-8.65 by titration with 0.5 N NaOH. At threeminutes, 10 mg of CaCO₃ is added and the pH is recorded. The decrease inpH is directly correlated to the amount of CaCO₃ that precipitates. Theadditive concentration in the final test solution is 2.7 ppm.

                  TABLE 3                                                         ______________________________________                                        Sample            percent of                                                                              CaCO.sub.3                                        from              equivalence                                                                             Drift                                             Example Number    of NH.sub.3                                                                             (pH units)                                        ______________________________________                                        blank                       1.05                                              1                 90        0.60                                              2                 75        0.63                                              3                 50        0.53                                              4                 25        1.05                                              a                 100       0.88                                              6a                100       0.60                                              polyaspartate               0.44                                              2000 mol. wt. polyacrylate  0.37                                              4500 mol. wt. polyacrylate  0.20                                              ______________________________________                                         .sup.a prepared by the method of Example 1 using 1 equivalent of ammonia 

EXAMPLE 9. Dispersant activity.

Kaolin dispersion was run by placing the sample (final concentration of20 ppm) in a 12×100 mm test tube containing 5 ml of deionized water andadding 40,000 ppm kaolin clay. The height of the suspended solids wasmeasured and compared to a control in which no dispersant had beenadded. A higher value indicates better dispersancy. Table 4 gives theresults.

                  TABLE 4                                                         ______________________________________                                        Sample         percent of  Kaolin clay                                        from           equivalence height (mm)                                        Example Number of NH.sub.3 suspension                                                                              settled                                  ______________________________________                                        blank                      0         15                                       1              90                                                             2              75          47        3.5                                      3              50          48        2.5                                      4              25          48        2.5                                      a              100         50        3                                        6a             100                                                            polyaspartate                                                                 2000 mol. wt. polyacrylate 48        2                                        4500 mol. wt. polyacryfate 48        3                                        ______________________________________                                         .sup.a prepared by the method of Example 1 using 1 equivalent of ammonia 

EXAMPLE 10 pH drift assay for calcium phosphate.

A solution which is supersaturated with calcium phosphate was preparedby adding 0.1 ml of previously prepared aqueous solutions of 1.32 MCaCl₂ dihydrate and 0.90 M NaH₂ PO₄ to 29.8 ml of distilled water,resulting in 4.4 mM Ca²⁺ and 3.0 mM dissolved inorganic phosphorus. Thereaction vessel is maintained at 25° C. There is considerableirregularity in the time necessary to begin precipitation. Calciumphosphate begins to crystalize within a few minutes of initiation (firstdrop in pH) and is transformed to hydroxyapatite, Ca₁₀ (PO₄)₆ (OH)₂,with a consequent downward pH drift (second drop in pH). The reactionceases when the reactants are depleted and the pH ceases its downwarddrift. The samples prepared in Examples 1-4 and 6 were tested and theresults (the average of two separate runs) are given in Table 5.

                  TABLE 5                                                         ______________________________________                                        Sample from     percent of                                                                              Induction                                           Example         equivalence                                                                             period                                              Number          of ammonia                                                                              (min)                                               ______________________________________                                        blank                     17.5                                                                100       34.5                                                1               90        30.5                                                2               75        41                                                  3               50        34                                                  4               25        29.5                                                a               100       26.5                                                6               75        34.5                                                6a              100       27                                                  polyaspartic acid         37                                                  ______________________________________                                         .sup.a prepared by the method of Example 1 using 1 equivalent of ammonia 

EXAMPLE 11. Maleic anhydride with 99% of a theoretical equivalent of NH₃

Maleic anhydride, 39.2 g (0.4 moles) dissolved in 40 g of water wasadded to 43.1 g of aqueous NH₄ OH (6.7 g NH₃, 0.394 moles) and tumbledat 180°-195° C. for 8 min to give a clear pink melt. It was then heatedto 185°-200° C. for 10 min to give a pink foam. The pulverized foam washeated for 10 min at 200°-235° C. to give a pink powder and then heatedat 235°-245° C. for 10 min to give 38.5 g of a pink tan powder. Thematerial was hydrolyzed with aqueous NaOH. The GPC gave a peak at 23min. In the CaSO₄ assay of Example 7, the blank was 83 mg while thesample at 2.5 ppm gave a precipitate of 11 mg and at 1.25 ppm it gave aprecipitate of 41 mg. In the Kaolin dispersion test of Example 9, at 20ppm the height of suspended solids was 48 mm whereas the blank was 0 mm.

EXAMPLE 12. Maleic anhydride with 5% of a theoretical equivalent of NH₃

Maleic anhydride, 39.2 g (0.4 moles) dissolved in 40 g of water wasadded to 4.3 g of aqueous NH₄ OH (0.34 g NH₃, 0.02 moles) and tumbled at180°-195° C. for 12 min to give a tan melt. It was then heated to200°-225° C. for 10 min to give a tan melt. The melt was heated for 10min at 220°-230° C. to give 18.1 g of brown solid. The material washydrolyzed with aqueous NaOH. In the CaSO₄ assay of Example 7, the blankwas 80 mg while the sample at 2.5 ppm gave a precipitate of 50 mg and at1.25 ppm it gave a precipitate of 78 mg.

EXAMPLE 13. Preparation of a maleic polymer with a polyamine

To a solution of 1.9 g (0.025 moles) of ethylene diamine in 40 g ofwater containing 1.0 g of NaOH was added 39.2 g (0.4 moles) of maleicanhydride while stirring at 70°-25° C. for 10 min to give a white slurryof maleic acid. To this slurry was added 21.7 g of water containing 1.7g (0.1 moles) of ammonia with stirring and cooling. This solution wasthen heated for 15 min at 170°-200° C. to give a tan melt. The melt washeated at 200°-225° C. for 10 min to give 36.5 g of a tan melt. It wasfurther heated at 225°-235° C. for 10 min to give 35.4 g of tan meltwhich was not soluble in water.

The powder was dissolved in a solution of 9.0 g of water containing 1.3g of NaOH to give a clear red-brown solution, estimated to contain 36%solids. In the CaSO₄ assay of Example 7, the blank was 80 mg while thesample at 2.5 ppm gave a precipitate of 22 mg and at 1.25 ppm it gave aprecipitate of 66 mg. The GPC showed a peak at 29.5 min with a broadshoulder at 21-25 min.

EXAMPLE 14. Preparation of a maleic polymer with maleamic acid.

A solution of 9.8 g (0.1 mole) maleic anhydride in 40 g of water wasstirred 45 min at 75°-25° C. To this solution was added 34.5 g (0.3mole) of maleamic acid. The slurry was tumbled at 180°-195° C. for 10min. All of the solids dissolved to give 39.9 g of a viscous red-tansyrup. Upon further heating for six 10 min periods at 180°-240° C., atan powder, insoluble in water, was obtained. A 3.9 g portion wasdissolved in 10 g of water containing 1.6 g of NaOH. The GPC showed apeak at 22.5 min. In the CaSO₄ assay of Example 7, the blank was 86 mgwhile the sample at 2.5 ppm gave a precipitate of 11 mg.

EXAMPLE 15. Preparation of a maleic polymer with diethylene triamine andoleic acid.

A mixture of 2.0 g (0.0175 moles) of diethylene triamine and 1.13(0.0195 moles) of oleic acid was heated with stirring for 10 min at190°-210° C. The resulting oil was dissolved in 50 g of methanol. Tothis solution of 9.8 g (0.1 mole) maleic anhydride in 40 g of water wasstirred 45 min at 75°-25° C. To this solution was added 39.0 g (0.4mole) of maleic anhydride. The reactants were stirred 45 min, followingwhich 4.3 g (0.25 mole) of ammonia in 20 g of water was added (75% of anequivalent). The slurry was tumbled at 170°-185° C. for 10 min. Uponfurther heating for four 10 min periods at 190°-245° C., 42.3 g of a tanpowder, insoluble in water, was obtained. A 4.0 g portion was dissolvedin 10 g of water containing 1.6 g of NaOH. The GPC showed two broadpeaks at 14 and 24 min. In the CaSO₄ assay of Example 7, the blank was86 mg while the sample at 2.5 ppm gave a precipitate of 8 mg. In theKaolin dispersion test of Example 9, at 20 ppm the height of suspendedsolids was 48 mm whereas the blank was 0 mm.

EXAMPLE 16. Preparation of a maleic polymer with oleyl amine.

To a solution of 2.67 g (0.01 mole) oleyl amine in 50 g of methanol wasadded 39.2 g (0.4 mole) maleic anhydride with stirring for 45 min at 25°C., following which 5.0 g (0.29 mole) of ammonia in 20 g of water wasadded (75% of an equivalent). The slurry was tumbled at 170°-195° C. for10 min. Upon further heating for four 10 min periods at 200°-235° C.,41.4 g of a brittle glass, insoluble in water, was obtained. Thematerial was dissolved in 100 g of water containing 16 g of NaOH. Tothis solution was added 5.5 g of 30% H₂ O₂. After 16 hrs at 25° C., thesolution was a clear yellow color. The GPC showed a peak at 14 min. Inthe CaSO₄ assay of Example 7, the blank was 86 mg while the sample at2.5 ppm gave a precipitate of 9 mg.

It will be apparent to those skilled in the art that the examples andembodiments described herein are by way of illustration and not oflimitation, and that other examples may be utilized without departingfrom the spirit and scope of the present invention, as set forth in theappended claims.

We claim:
 1. A polymer produced by a process comprising polymerizing (1)one of the members of the group consisting of maleic acid, malic acid,or fumaric acid, (2) less than one equivalent of ammonia and (3) anamine, at a temperature greater than about 120° C., to produce saidpolymer.
 2. The polymer of claim 1 wherein the amine has at least oneprimary amine and additional amine groups consisting of at least one ormore primary or secondary amines.